Rämä Teppo, Davey Marie L, Nordén Jenni, Halvorsen Rune, Blaalid Rakel, Mathiassen Geir H, Alsos Inger G, Kauserud Håvard
Tromsø University Museum, UiT The Arctic University of Norway, Tromsø, Norway.
Marbio, UiT The Arctic University of Norway, Tromsø, Norway.
Microb Ecol. 2016 Aug;72(2):295-304. doi: 10.1007/s00248-016-0778-9. Epub 2016 May 4.
High amounts of driftwood sail across the oceans and provide habitat for organisms tolerating the rough and saline environment. Fungi have adapted to the extremely cold and saline conditions which driftwood faces in the high north. For the first time, we applied high-throughput sequencing to fungi residing in driftwood to reveal their taxonomic richness, community composition, and ecology in the North Atlantic. Using pyrosequencing of ITS2 amplicons obtained from 49 marine logs, we found 807 fungal operational taxonomic units (OTUs) based on clustering at 97 % sequence similarity cut-off level. The phylum Ascomycota comprised 74 % of the OTUs and 20 % belonged to Basidiomycota. The richness of basidiomycetes decreased with prolonged submersion in the sea, supporting the general view of ascomycetes being more extremotolerant. However, more than one fourth of the fungal OTUs remained unassigned to any fungal class, emphasising the need for better DNA reference data from the marine habitat. Different fungal communities were detected in coniferous and deciduous logs. Our results highlight that driftwood hosts a considerably higher fungal diversity than currently known. The driftwood fungal community is not a terrestrial relic but a speciose assemblage of fungi adapted to the stressful marine environment and different kinds of wooden substrates found in it.
大量浮木漂洋过海，为耐受恶劣咸水环境的生物提供了栖息地。真菌已适应了浮木在高纬度地区所面临的极寒和高盐条件。我们首次对浮木中的真菌应用高通量测序，以揭示它们在北大西洋的分类丰富度、群落组成和生态学特征。通过对从49块海洋原木中获得的ITS2扩增子进行焦磷酸测序，我们在97%序列相似性截止水平上聚类得到了807个真菌操作分类单元（OTU）。子囊菌门占OTU的74%，担子菌门占20%。担子菌的丰富度随着在海水中浸泡时间的延长而降低，这支持了子囊菌更耐受极端环境的普遍观点。然而，超过四分之一的真菌OTU仍未被归入任何真菌类群，这凸显了需要更好的来自海洋栖息地的DNA参考数据。在针叶木和落叶木原木中检测到了不同的真菌群落。我们的结果表明，浮木所承载的真菌多样性比目前已知的要高得多。浮木真菌群落并非陆地遗迹，而是适应了恶劣海洋环境及其中不同类型木质基质的丰富真菌组合。
